MLA

Van Vechten, Carl, 1880-1964. Atkinson, Edward. Box 83, folder 1360. 1942 February 6. https://collections.library.yale.edu/catalog/2020434.

APA, 6th edition

Van Vechten, Carl, 1880-1964. (["Box 83, folder 1360"])(1942 February 6)[Atkinson, Edward]. https://collections.library.yale.edu/catalog/2020434.